@book{gamma:94,
	author = {Erich Gamma and Richard Helm and Ralph Johnson and John Vlissides (the gang of four)},
	title = {Design Patterns -- Elements of Reusable Object Oriented Software},
	publisher = {Addison-Wesley},
	year = {1994},
}
@book{lanza:06,
	author = {Michele Lanza and Radu Marinescu},
	title = {Object-Oriented Metrics in Practice -- Using Software Metrics to Characterize, Evaluate, and Improve the Design of Object-Oriented Systems},
	publisher = {Springer},
	year = {2006},
}